There were two problems with enabling the PRINTK_TIME config
option:
1) The first calls to printk() occur before per-cpu data virtual
address is pinned into the TLB, so sched_clock() can fault.
2) sched_clock() is based on ar.itc, which may not be synchronized
across cpus.
Ken Chen started this patch, Tony Luck tinkered with it, and Jes
Sorensen perfected it.
Signed-off-by: Tony Luck <tony.luck@intel.com>
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